Fly back, beginning to organise dance (5)
I believe the answer is:
tango
'dance' is the definition.
(tangoing is a kind of dancing)
'fly back beginning to organise' is the wordplay.
'fly' becomes 'gnat' (I've seen this before**).
'back' says the letters should be written backwards.
'beginning to' suggests taking the first letters.
The initial letter of 'organise' is 'o'.
'gnat' back-to-front is 'tang'.
'tang'+'o'='TANGO'
(Other definitions for tango that I've seen before include "Dance originally from Buenos Aires" , "Movement from Argentina" , "tee" , "Steps" , "something seen in ballroom?" .)